‘Major leap forward’ in AD prevention research
PHILADELPHIA – in age-dependent fashion, compared with the older target standard BP, according to a novel analysis of data from the landmark SPRINT trial.
Bruce Jancin/MDedge News
Dr. Muthiah Vaduganathan
SPRINT randomized 9,361 hypertensive patients aged 50 years or older with at least one additional cardiovascular risk factor to intensive control with a target systolic BP of less than 120 mm Hg or to the then-standard target of less than 140 mm Hg. The trial was stopped early for ethical reasons when an interim analysis showed intensive control was associated with a 27% reduction in mortality. But that 27% reduction in mortality risk is a tough concept for many patients to interpret in practical terms, Muthiah Vaduganathan, MD, observed at the American Heart Association scientific sessions.
So he and his coinvestigators sliced and diced the mountainous SPRINT data in a novel way, using an actuarial statistical analysis.
“These actuarial data from SPRINT support the survival benefits of intensive blood pressure control, especially when initiated in middle-aged, high-risk adults. Our analysis really reaffirms the original SPRINT trial results [N Engl J Med. 2015 Nov 26;373(22):2103-16] and helps present them in an alternative format that can potentially be more easily communicated to clinicians, patients, and the public at large,” explained Dr. Vaduganathan, a cardiologist at Brigham and Women’s Hospital and Harvard Medical School, both in Boston.
The impact of intensive BP control on residual survival was magnified in patients who were younger, since they intrinsically have a longer expected survival and will apply the antihypertensive regimen over a longer period. For example, the actuarial analysis concluded that the mean survival benefit of starting intensive BP lowering, rather than settling for a target systolic BP of less than 140 mm Hg starting at age 50 years, was 3 additional years of life, as compared with 1.1 additional years in 65-year-olds and 0.5 years in patients aged 85 years or older. The same approach can be applied to patients at any individual age from 50 to 95 years at the time of enrollment.
“This is very helpful in conveying messages to individual patients. Often if you tell a patient: ‘Your risk is going to go down by 27%,’ it’s tough for them to recognize what the baseline is and if that actually applied to them. So this may personalize that decision-making conversation,” according to the cardiologist.
One audience member commented that this SPRINT analysis might actually underestimate the true survival advantage of intensive BP lowering. He noted that SPRINT, which was halted after an average of 3.3 years, didn’t show a significant benefit for intensive BP lowering in terms of stroke reduction, whereas the ACCORD trial did, but that benefit didn’t occur until after 3 years into the study (Hypertension. 2018 Aug;72[2]:323-30).
Dr. Vaduganathan conceded that’s a limitation of his analysis.
“The assumption we’ve used is that long-term cardiovascular benefits are going to be as seen in the trial, but since SPRINT was stopped early, some benefits may be exaggerated and some may not have been observed yet,” he agreed.
Another audience member observed, “I think a lot of patients will think: ‘Okay, you’re tacking on a year at the end, when I’m going to be 89 and demented.’ The National Institute on Aging is focusing a lot more now on nondisabled life expectancy or healthy life expectancy.’”
Dr. Vaduganathan offered a degree of reassurance on this score. Because of time limitations, he said, he only presented the life expectancy results. But he and his coworkers have performed the same actuarial analysis of the SPRINT data for other endpoints related to freedom from various forms of disease or disability and found a consistent effect: Intensive BP control was associated with a longer time to onset of morbidity.
SPRINT was sponsored primarily by the National Heart, Lung, and Blood Institute. Dr. Vaduganathan reported that he receives research support from/and or serves on advisory boards for Amgen, AstraZeneca, Baxter Healthcare, Bayer, Boehringer Ingelheim, and Relypsa.
SOURCE: Vaduganathan M et al. AHA 2019, Abstract MDP233.